I have exactly the same issue LVM not getting mounted on boot and I can always mount it from recovery shell maybe udev rule /lib/udev/rules.d/85-lvm2.rules doesn't get executed.. or /lib/udev/rules.d/56-lvm.rules
I have exactly the same issue LVM not getting mounted on boot and I can always mount it from recovery shell rules.d/ 85-lvm2. rules doesn't get executed.. rules.d/ 56-lvm. rules
maybe udev rule /lib/udev/
or /lib/udev/